Can you find out the remainder when 3^300 is divided by 5?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

If in a car race, the man who came two places in front of the last man finished one ahead of the man who came fifth, how many contestants were there?

What will be the best approach to finding all the prime numbers less than 75 that leave an odd reminder when we divide them with 5?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

We know that the number 7 is the prime followed by a cube. Which next number is also a prime followed by a cube?

If nine thousand, nine hundred nine dollars is written as $9,909,
how should twelve thousand, twelve hundred twelve dollars be written?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

John can eat 27 chocolates in an hour, Jacob can eat 2 chocolates in 10 minutes, and Jolly can eat 7 chocolates in 20 minutes. How long will it take them to share and eat a box of 120 chocolates whilst playing Chess?

How many people must be gathered together in a room, before you can be certain that there is a greater than 50/50 chance that at least two of them have the same birthday?